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[Bug target/69008] gcc emits unneeded memory access when passing trivial structs by value (ARM)
- From: "ktkachov at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 22 Dec 2015 10:05:14 +0000
- Subject: [Bug target/69008] gcc emits unneeded memory access when passing trivial structs by value (ARM)
- Auto-submitted: auto-generated
- References: <bug-69008-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69008
ktkachov at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2015-12-22
CC| |ktkachov at gcc dot gnu.org
Ever confirmed|0 |1
Known to fail| |4.8.5, 4.9.4, 5.3.1, 6.0
--- Comment #1 from ktkachov at gcc dot gnu.org ---
Confirmed on all versions that I have access to.
The expander emits:
(insn 2 5 3 2 (set (reg:SI 113)
(plus:SI (reg/f:SI 105 virtual-stack-vars)
(const_int -8 [0xfffffffffffffff8]))) missed.c:7 -1
(nil))
(insn 3 2 4 2 (parallel [
(set (mem/c:SI (reg:SI 113) [1 t+0 S4 A32])
(reg:SI 0 r0))
(set (mem/c:SI (plus:SI (reg:SI 113)
(const_int 4 [0x4])) [1 t+4 S4 A32])
(reg:SI 1 r1))
]) missed.c:7 -1
(nil))
(note 4 3 7 2 NOTE_INSN_FUNCTION_BEG)
(insn 7 4 8 2 (set (reg:SI 115)
(mem/c:SI (plus:SI (reg/f:SI 105 virtual-stack-vars)
(const_int -8 [0xfffffffffffffff8])) [2 t.i1+0 S4 A32]))
missed.c:8 -1
(nil))
(insn 8 7 9 2 (set (reg:SI 116)
(mem/c:SI (plus:SI (reg/f:SI 105 virtual-stack-vars)
(const_int -4 [0xfffffffffffffffc])) [2 t.i2+0 S4 A32]))
missed.c:8 -1
(nil))
(insn 9 8 10 2 (set (reg:SI 114)
(plus:SI (reg:SI 115)
(reg:SI 116))) missed.c:8 -1
(nil))